Artificial leg



(No Model.)

W. ANDREWS.

ARTIFICIAL LEG.

No. 518,658. Patented Apr. 24, 1894.

WITNESSES. n INVENTOR ATTORNEY.

Inward m n c Nr'rnn STATES PATENT ()rricn.

WILLIAM ANDREWS, OF LOWELL, MASSACHUSETTS.

ARTIFICIAL LEG.

SPECIFICATION forming part of Letters Patent No. 518,658, dated April24,1894.

Application filed September 30, 1 892. Serial No.44'7,388. (No model.)

To all whom it may concern:

Be it known that I, WILLIAM ANDREWS, a citizen of the United States,residing at Lowell, in the county of Middlesex and Commonof the foot;and an improved construction of the toe-spring.

In the accompanying drawings, Figure 1 is a side elevation of a legconstructed in accordance with my improvement; Fig. 2, a verticallongitudinal section of a leg and foot embodying said improvement; Fig.3, a section on the line 3 3 in Fig. 2; Fig. 4, a plan of the foot,detached, showing the means by which it is secured to the leg; Fig. 5, atransverse section on the line 5 5 in Fig. 2 of the core, the upper partof the attaching-bolt being broken away; Fig. 6, a vertical longitudinalsection of a part of the foot and the adjacent part of the leg, showinga modification of the core; Fig. 7, a transverse section on the line 7 7in Fig. 6.

The thigh-pieceA, provided with buttons a, to engage a strap passed overthe shoulder of the wearer, the metallic hinge B, uniting the lacer orthigh-piece A to the shell or socket O and said shell are of any usualconstruction and operation, except that thelower end of said shell isadapted to receive the core-bo1ts, steady-plate and steady-pins and theupper part of the elastic envelope of the core as hereinafter described.

The core D of the foot herein described is rigidly secured to the leg orshell 0 and the absence of an. ankle-joint is compensated for by theelasticity of the heel and toe-portions of the foot. The core 1) ispreferably of aluminum or any of its alloys, combining sufficientstrength with small weight, and is pro- Vltlvtl at the top with anoblong steady-plate d which enters and fits a corresponding recess c inthe lower end of the shell 0 and with one or more vertical bolts (1 (1(one being shown in Fig. 2 and two being shown in Fig. 6), said boltspassing up through holes 0' c in the lower end of said shell into thecavity a of said shell and being held therein bynuts d d which engagethe threaded upper ends d d of said bolts and are turned down uponwashers d 01 surrounding said bolts and resting upon the bottom of saidcavity c The oblong shape of the steady-plate tends to prevent the coreD and shell 0 from turning on each other and this purpose is furtherserved, where but a single core-bolt d (Fig. 2) is used, by one or moresteady-pins d 01 projecting upward from the steady-plate and enteringcorresponding holes (2 c in the lower end of the shell.

To the under side of the steady-plate d is secured adownwardly-projecting pin or knob d which serves to hold the elasticenvelope E, hereinafter described, more securely in place and to preventthe same from buckling or bending laterally, The body of the core Dbelow the steady-plate d has a front al or instep portion which runsfrom the steadyplate forward and downward, substantially parallel withthe instep of the finished foot to the ball of the same, a'sole d whichextends from the ball of the foot to a point below and infront of theankle-joint, and a back 01 which extends from a point in the rear of thesole (1 to the bottom of the steady-plate, the junction of said sole andback being a curved protuberance 01 which serves as a backing orresistance for the heel cushion e hereinafter described. The sole d ofthe core is widest at the ball of the foot and is gradually narrowedtoward the resistance d which is broadened out laterally to support thepressure of said heel-cushion.

The front c1 sole (1 and back at of the core may be connected bya thinvertical web at, as in Figs. 2, 3 and 5, to strengthen the core, or theother parts of the core being made of sufficient strength, said web maybe omitted and the open space left by such omission filled with theelastic material which forms the envelope, as shown in Fig. 6.

All the parts of the core, the core-bolts, steady-plate, steady-pins (ifsuch are used) and the knob cl are rigidly secured to each other,preferably by casting all of the same in one piece.

After the core is properly formed, by means of a suitable rubber cement,a thin layer 6 of rubber which becomes hard when vulcanized is appliedto the entire surface of the core below the steady-plate d, so that saidlayer 6 becoming rigid may remain in place and prevent any slipping onthe core of the succeedinglayers of rubber, and another thin layer e ofrubber which becomes soft and spongy when vulcanized is laid over thecore from the instep to the back of the core and the toe-spring F iscemented to the layer 6' of sponge-rubber. The toe-spring has twomembers, the upperf of which extends from about the instep of thefinished foot beyond the front end or toe of the core D, the lowermemberf' extending from the front end of the upper member about to theresistance 01 and each membericonsisting of two or more rows of cords ff the cords of each row being arranged at intervals from each other andembedded in rubber which becomes hard and springy when vulcanized, andthe cords of I one row being arranged opposite the intervals between thecords of the other row of the same member and each row being separatedfrom the other row of the same mem' her by a thin layer of soft orsponge'rubber. The hard rubber is by any suitable means caused tocompletely surround each cord of the toe-spring. I

I do not herein claim any combination which includes the toe-springbecause I have shown, described and claimed substantially such aspringin combinations similar to those herein shown and described in anotherapplication, Serial No. 42 9,281, filed by me April 15, 1892, and nowpending. 1 By the arrangement above described a stronger and moreelastic spring can be made by the use of a greater number of smallercords. After the toe-spring is in place, said toe-spring and the core upto the bottom of the steady-plate are covered with an elastic envelopeE, preferably rubber which becomes sponge-rubber when vulcanized and theenvelope is made in a suitable mold to take the shape of the naturalfoot, then vulcanized in the usual manner, the top of the foot, where itjoins the leg, being left substantially flat. The top of the foot, whenthe foot is attached to the leg, is so compressed into a concavity cwith which the lower end of the leg or shell is provided that thepressure upon any part of the rubber envelope will not draw any otherpart of said envelope away from the lower end of said shell and that acompression of any part of the envelope will not cause it to roll overthe lower end of said shell. By this means the adjacent surfaces of theleg or shell and of the foot are kept continuous with each other at alltimes. This construction of the shell, with a concavity 0 into which thetop of the rubber envelope is compressed, 1's

equally applicable to a foot movably jointed to such shell.

It will be seen that the construction described secures a very largeheel-cushion e, the rear portion of the foot, back of the place of theankle-joint in the natural foot, being nearly all rubber, and preventsany shock when the foot is placed with considerable force upon theground, as in jumping, and that said heel-cushion a with the elastictoespring enables the natural walk to be very closely imitated withoutthe use of an anklejoint.

The elastic envelope of sponge-rubber adheres sufficiently to a woodencore although liable to separate from a metallic core, but by placing alayer of hard rubber next the metallic core, the envelope may beproperly secured, the hard rubber adhering to the metal and thesponge-rubber to the hard rubber. It will be understood that every layerof rubber is cemented to the next inner layer, in the usual manner.

I claim as my invention- 1. The combination of the shell, an elasticenvelope, an inelastic core arranged therein and an attaching bolt,rigidly secured to said core and entering said shell, as and for thepurpose specified.

2. The combination of the shell, an elastic envelope, and a metalliccore, provided with an attaching-bolt and with steady pins formed in onepiece with said core, as and for the purpose specified.

3. The combination'of the shell, an elastic envelope and acore, providedwith an attaching-bolt and with an oblong steady-plate, arranged toenter and fill a recess with which the lower end of said shell isprovided, and a downward projection secured on said steadyplate to entersaid envelope, as and for the purpose specified.

4.. An artificial foot consisting of an inelastic core and an elasticenvelope of the shape of the natural foot, the bottom of said coreextending from below the place of the natural ankle-joint to the ball ofthe foot and said elastic envelope filling the entire space back of theplace of said natural ankle-joint, as and for the purpose specified.

5. The combination of the leg or shell, having a concavity in the lowerend and a foot attached to said leg and having an elastic upper surfacecompressed into said concavity, as and for the purpose specified.

6. The combination, in an artificial foot, of the core, a layer of hardrubber next the core and an outer elastic covering, as and for thepurpose specified.

In witness whereof Ihave signed this specification, in the presence oftwo attesting witnesses, this 26th day of September, A. D. 1892.

WILLIAM ANDREWS. WVitnesses:

ALBERT M. Moons, MYRTIE G. BEALS.

